Electric power source used with vehicles

Abstract

An electric power source used with a vehicle includes: a battery block composed of a rechargeable battery; a cooling plate thermally coupled with the battery block to cool the battery; a cooling mechanism for cooling the cooling plate; and a controller for controlling the cooling mechanism to switch the cooling plate into a cooled state and an uncooled state. The controller controls the cooling mechanism both in accordance with temperature of the battery block and temperature of the cooling plate, and switches the cooling plate into the cooled state and the uncooled state.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention generally relates to an electric power source being used with an electric vehicle such as a hybrid car, and particularly to an electric power source for cooling a battery block by means of a cooling plate.[0003]2. Description of the Related Art[0004]The electric power source to be mounted on a hybrid car or the like is required of forcibly cooling a battery which will generate heat when the battery is charged and discharged at a large current. This is because temperature increase of the battery causes electrical characteristics of the battery to decrease as well as shortens a duration of life of the battery and further causes safety to be inhibited. In order to prevent such harmful results, there have been developed a power source in which a battery is cooled by means of air (JP 2006-252847-A) and a power source in which a battery is cooled by means of a cooling plate (Japanese Utility Model Regist...

AI Technical Summary

Benefits of technology

[0010]The above-described electric power source can cool the battery in an ideal state while preventing the moisture in the air from dew formation. Particularly, since the electric power source is so designed as to directly cool the battery by thermally coupling the battery block with the cooling plate instead of cooling the battery by blowing the air, the battery is quickly and efficiently cooled while the cooling plate can also be prevented from the dew formation. In particular, the electric power source of the present invention can control the cooling plate not to have the dew formation, by controlling the cooling mechanism in accordance with the temperature of the battery block and the temperature of the cooling plate instead of controlling by detecting that the dew has been formed. Therefore, the electric power source is distinctive in that the battery can be quickly and quietly cooled while the dew formation is prevented.

[0021]The electric power source, with its cooling plate being of uniform temperature, can uniformly cool the battery of the battery block. This is made possible because the parallel pipe on the outlet side with the temperature being liable to be elevated is disposed adjacent to the parallel pipe with the lower temperature on the inlet side. The cooling pipe where a / the plurality of parallel pipes are cooled in a series connection is designed to cool the battery by means the refrigerant being flowed from the inlet side and to exhaust the refrigerant from the outlet side. The cooling plate supplies the refrigerant to the cooling pipe via the expansion valve such as the capillary tube. Supplied into the cooling pipe is a liquefied refrigerant. The refrigerant, when passing through the cooling pipe, is evaporated and fed to the outlet side. When the temperature of the cooling plate is high, the refrigerant supplied to the cooling pipe from the capillary tube which does not control a quantity of supply of the refrigerant may sometimes be fully evaporated en route. In such a state, the evaporated refrigerant but not the liquefied refrigerant is supplied to the parallel pipe on the outlet side, and thus the cooling effect by the evaporation heat becomes smaller. However, since the electric power source is so designed as to dispose the parallel pipe on the outlet side adjacent to the parallel pipe on the inlet side, the battery is efficiently cooled by the parallel pipe on the inlet side even if the cooling effect by the parallel pipe on the outlet side becomes smaller,. This is because the parallel pipe on the inlet side has a sufficient amount of liquefied refrigerant to effectively cool the battery.

Problems solved by technology

This is because temperature increase of the battery causes electrical characteristics of the battery to decrease as well as shortens a duration of life of the battery and further causes safety to be inhibited.

When the dew is formed and the fan stops its operation, the amount of dew formation does not increase, but disadvantageously a concentrated state lasts longer because the moisture formed into the dew cannot evaporate to be dried.

Further, when the battery temperature is higher than preset temperature in a state of dew formation, the fan is in operation; in such a state, however, since the air is to be forcibly blown in a state of forming the dew, the moisture contained in the air being fed from time to time is formed to dew at a portion that is cooled by low temperature, resulting in an adverse effect that the dew formation gradually increases temporarily.

However, when the battery temperature increases and the temperature of the blown air increases, the dew is not formed; but when there exists a local portion with lower temperature, such portion cannot be prevented from the dew formation.

Therefore, the power source as described in JP 2006-252847 suffers a difficulty of efficiently cooling the battery while preventing the dew formation.

In particular, since the battery is cooled by air with smaller specific heat, it is difficult to quickly cool the battery in a state where the heat value of the battery is large.

As can be seen in the characteristics shown in FIG. 1, the cooling plate being cooled to low temperature cannot prevent the dew from being formed on the plate surface because the amount of moisture in the air decreases.

In view of this aspect, the power source in which the battery is directly cooled by means of the cooling plate suffers a difficulty that the dew formation on the surface of cooling plate is prevented while the battery is efficiently cooled.

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